diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
new file mode 100644
index 00000000..91106d3f
--- /dev/null
+++ b/.github/workflows/maven.yml
@@ -0,0 +1,17 @@
+name: Java CI
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up JDK 1.8
+      uses: actions/setup-java@v1
+      with:
+        java-version: 1.8
+    - name: Build with Maven
+      run: mvn -B package --file pom.xml
diff --git a/src/main/java/cc/moecraft/icq/event/Event.java b/src/main/java/cc/moecraft/icq/event/Event.java
index b79c4313..9515cdac 100644
--- a/src/main/java/cc/moecraft/icq/event/Event.java
+++ b/src/main/java/cc/moecraft/icq/event/Event.java
@@ -21,7 +21,7 @@ public abstract class Event implements ContentComparable
 {
     @SerializedName("post_type")
     @Expose
-    public String postType;
+    protected String postType;
 
     @SerializedName("self_id")
     @Expose
@@ -29,9 +29,9 @@ public abstract class Event implements ContentComparable
 
     @SerializedName("time")
     @Expose
-    public Long time;
+    protected Long time;
 
-    public PicqBotX bot;
+    protected PicqBotX bot;
 
     public Event setBot(PicqBotX bot)
     {
diff --git a/src/main/java/cc/moecraft/icq/event/events/local/EventLocal.java b/src/main/java/cc/moecraft/icq/event/events/local/EventLocal.java
index 9f28ab12..61f88059 100644
--- a/src/main/java/cc/moecraft/icq/event/events/local/EventLocal.java
+++ b/src/main/java/cc/moecraft/icq/event/events/local/EventLocal.java
@@ -13,5 +13,5 @@
 @NoArgsConstructor
 public abstract class EventLocal extends Event
 {
-    public boolean cancelled = false;
-}
+    protected boolean cancelled = false;
+}
\ No newline at end of file
diff --git a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpFail.java b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpFail.java
index bbcba53d..b8ef82cf 100644
--- a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpFail.java
+++ b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpFail.java
@@ -13,7 +13,7 @@
 @AllArgsConstructor
 public class EventLocalHttpFail extends EventLocal
 {
-    public Reason fail; // 怎样失败的
+    protected Reason fail; // 怎样失败的
 
     public enum Reason
     {
diff --git a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpReceive.java b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpReceive.java
index c78379d9..056de3c6 100644
--- a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpReceive.java
+++ b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalHttpReceive.java
@@ -16,15 +16,15 @@
 @Data
 public class EventLocalHttpReceive extends EventLocal
 {
-    public String[] info;
+    protected String[] info;
 
-    public ArrayList<String> otherInfo;
+    protected ArrayList<String> otherInfo;
 
-    public String contentType;
+    protected String contentType;
 
-    public String charset;
+    protected String charset;
 
-    public String userAgent;
+    protected String userAgent;
 
-    public String data;
+    protected String data;
 }
diff --git a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalSendMessage.java b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalSendMessage.java
index b7315ba9..49eb6aae 100644
--- a/src/main/java/cc/moecraft/icq/event/events/local/EventLocalSendMessage.java
+++ b/src/main/java/cc/moecraft/icq/event/events/local/EventLocalSendMessage.java
@@ -13,11 +13,11 @@
 @Data
 public class EventLocalSendMessage extends EventLocal
 {
-    public long id;
+    protected long id;
 
-    public String message;
+    protected String message;
 
-    public boolean autoEscape = false;
+    protected boolean autoEscape = false;
 
     public EventLocalSendMessage(long id, String message)
     {
diff --git a/src/main/java/cc/moecraft/icq/event/events/message/EventDiscussMessage.java b/src/main/java/cc/moecraft/icq/event/events/message/EventDiscussMessage.java
index b7bf1f65..3de4889a 100644
--- a/src/main/java/cc/moecraft/icq/event/events/message/EventDiscussMessage.java
+++ b/src/main/java/cc/moecraft/icq/event/events/message/EventDiscussMessage.java
@@ -21,7 +21,7 @@ public class EventDiscussMessage extends EventGroupOrDiscussMessage
 {
     @SerializedName("discuss_id")
     @Expose
-    public Long discussId;
+    protected Long discussId;
 
     @Override
     public ReturnData<RMessageReturnData> respond(String message, boolean raw)
diff --git a/src/main/java/cc/moecraft/icq/event/events/message/EventGroupMessage.java b/src/main/java/cc/moecraft/icq/event/events/message/EventGroupMessage.java
index e729100b..ece7aa49 100644
--- a/src/main/java/cc/moecraft/icq/event/events/message/EventGroupMessage.java
+++ b/src/main/java/cc/moecraft/icq/event/events/message/EventGroupMessage.java
@@ -24,15 +24,15 @@ public class EventGroupMessage extends EventGroupOrDiscussMessage
 {
     @SerializedName("anonymous")
     @Expose
-    public Anonymous anonymous;
+    protected Anonymous anonymous;
 
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
     @Data
     @Setter(AccessLevel.NONE)
@@ -40,15 +40,15 @@ public class Anonymous
     {
         @SerializedName("flag")
         @Expose
-        public String flag;
+        protected String flag;
 
         @SerializedName("id")
         @Expose
-        public Long id;
+        protected Long id;
 
         @SerializedName("name")
         @Expose
-        public String name;
+        protected String name;
     }
 
     @Override
diff --git a/src/main/java/cc/moecraft/icq/event/events/message/EventMessage.java b/src/main/java/cc/moecraft/icq/event/events/message/EventMessage.java
index 0863eb1b..915376fd 100644
--- a/src/main/java/cc/moecraft/icq/event/events/message/EventMessage.java
+++ b/src/main/java/cc/moecraft/icq/event/events/message/EventMessage.java
@@ -23,11 +23,11 @@ public abstract class EventMessage extends Event
 {
     @SerializedName("message_type")
     @Expose
-    public String messageType;
+    protected String messageType;
 
     @SerializedName("font")
     @Expose
-    public Long font;
+    protected Long font;
 
     @SerializedName("message")
     @Expose
@@ -35,15 +35,15 @@ public abstract class EventMessage extends Event
 
     @SerializedName("message_id")
     @Expose
-    public Long messageId;
+    protected Long messageId;
 
     @SerializedName("raw_message")
     @Expose
-    public String rawMessage;
+    protected String rawMessage;
 
     @SerializedName("user_id")
     @Expose
-    public Long senderId;
+    protected Long senderId;
 
     /**
      * 回复消息
diff --git a/src/main/java/cc/moecraft/icq/event/events/message/EventPrivateMessage.java b/src/main/java/cc/moecraft/icq/event/events/message/EventPrivateMessage.java
index 23adc4e6..43a42e4e 100644
--- a/src/main/java/cc/moecraft/icq/event/events/message/EventPrivateMessage.java
+++ b/src/main/java/cc/moecraft/icq/event/events/message/EventPrivateMessage.java
@@ -20,7 +20,7 @@ public class EventPrivateMessage extends EventMessage
 {
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
     @Override
     public ReturnData<RMessageReturnData> respond(String message, boolean raw)
diff --git a/src/main/java/cc/moecraft/icq/event/events/notice/EventNotice.java b/src/main/java/cc/moecraft/icq/event/events/notice/EventNotice.java
index 1159e834..99041317 100644
--- a/src/main/java/cc/moecraft/icq/event/events/notice/EventNotice.java
+++ b/src/main/java/cc/moecraft/icq/event/events/notice/EventNotice.java
@@ -18,11 +18,11 @@ public class EventNotice extends Event
 {
     @SerializedName("notice_type")
     @Expose
-    public String noticeType;
+    protected String noticeType;
 
     @SerializedName("user_id")
     @Expose
-    public Long userId;
+    protected Long userId;
 
     @Override
     public boolean contentEquals(Object o)
diff --git a/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupBan.java b/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupBan.java
index 40af7166..8e287712 100644
--- a/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupBan.java
+++ b/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupBan.java
@@ -22,23 +22,23 @@ public class EventNoticeGroupBan extends EventNotice
 {
     @SerializedName("sub_type")
     @Expose
-    public BanType type;
+    protected BanType type;
 
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("operator_id")
     @Expose
-    public Long operatorId;
+    protected Long operatorId;
 
     @SerializedName("user_id")
     @Expose
-    public Long userId;
+    protected Long userId;
 
     @SerializedName("duration")
     @Expose
-    public Long duration;
+    protected Long duration;
 
     public enum BanType
     {
diff --git a/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupUpload.java b/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupUpload.java
index b32cb06f..8f80953f 100644
--- a/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupUpload.java
+++ b/src/main/java/cc/moecraft/icq/event/events/notice/EventNoticeGroupUpload.java
@@ -19,11 +19,11 @@ public class EventNoticeGroupUpload extends EventNotice
 {
     @SerializedName("file")
     @Expose
-    public File file;
+    protected File file;
 
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @Data
     @Setter(AccessLevel.NONE)
@@ -31,19 +31,19 @@ public class File
     {
         @SerializedName("busid")
         @Expose
-        public Long busid;
+        protected Long busid;
 
         @SerializedName("id")
         @Expose
-        public String id;
+        protected String id;
 
         @SerializedName("name")
         @Expose
-        public String name;
+        protected String name;
 
         @SerializedName("size")
         @Expose
-        public Long size;
+        protected Long size;
     }
 
     private GroupEventMethods groupMethods = null;
diff --git a/src/main/java/cc/moecraft/icq/event/events/notice/groupadmin/EventNoticeGroupAdminChange.java b/src/main/java/cc/moecraft/icq/event/events/notice/groupadmin/EventNoticeGroupAdminChange.java
index 9cc5dcde..808849a9 100644
--- a/src/main/java/cc/moecraft/icq/event/events/notice/groupadmin/EventNoticeGroupAdminChange.java
+++ b/src/main/java/cc/moecraft/icq/event/events/notice/groupadmin/EventNoticeGroupAdminChange.java
@@ -20,13 +20,13 @@ public class EventNoticeGroupAdminChange extends EventNotice
 {
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
-    private GroupEventMethods groupMethods = null;
+    protected GroupEventMethods groupMethods = null;
 
     @Override
     public boolean contentEquals(Object o)
diff --git a/src/main/java/cc/moecraft/icq/event/events/notice/groupmember/EventNoticeGroupMemberChange.java b/src/main/java/cc/moecraft/icq/event/events/notice/groupmember/EventNoticeGroupMemberChange.java
index 575660e1..a005b932 100644
--- a/src/main/java/cc/moecraft/icq/event/events/notice/groupmember/EventNoticeGroupMemberChange.java
+++ b/src/main/java/cc/moecraft/icq/event/events/notice/groupmember/EventNoticeGroupMemberChange.java
@@ -20,15 +20,15 @@ public class EventNoticeGroupMemberChange extends EventNotice
 {
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("operator_id")
     @Expose
-    public Long operatorId;
+    protected Long operatorId;
 
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
     private GroupEventMethods groupMethods = null;
 
diff --git a/src/main/java/cc/moecraft/icq/event/events/request/EventGroupAddRequest.java b/src/main/java/cc/moecraft/icq/event/events/request/EventGroupAddRequest.java
index ad53190d..4da290e6 100644
--- a/src/main/java/cc/moecraft/icq/event/events/request/EventGroupAddRequest.java
+++ b/src/main/java/cc/moecraft/icq/event/events/request/EventGroupAddRequest.java
@@ -18,11 +18,11 @@ public class EventGroupAddRequest extends EventRequest
 {
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
     @Override
     public void accept()
diff --git a/src/main/java/cc/moecraft/icq/event/events/request/EventGroupInviteRequest.java b/src/main/java/cc/moecraft/icq/event/events/request/EventGroupInviteRequest.java
index 3e379827..62f3fc7a 100644
--- a/src/main/java/cc/moecraft/icq/event/events/request/EventGroupInviteRequest.java
+++ b/src/main/java/cc/moecraft/icq/event/events/request/EventGroupInviteRequest.java
@@ -18,11 +18,11 @@ public class EventGroupInviteRequest extends EventRequest
 {
     @SerializedName("group_id")
     @Expose
-    public Long groupId;
+    protected Long groupId;
 
     @SerializedName("sub_type")
     @Expose
-    public String subType;
+    protected String subType;
 
     @Override
     public void accept()
diff --git a/src/main/java/cc/moecraft/icq/event/events/request/EventRequest.java b/src/main/java/cc/moecraft/icq/event/events/request/EventRequest.java
index ca2501b2..616f3c75 100644
--- a/src/main/java/cc/moecraft/icq/event/events/request/EventRequest.java
+++ b/src/main/java/cc/moecraft/icq/event/events/request/EventRequest.java
@@ -18,19 +18,19 @@ public abstract class EventRequest extends Event
 {
     @SerializedName("request_type")
     @Expose
-    public String requestType;
+    protected String requestType;
 
     @SerializedName("flag")
     @Expose
-    public String flag;
+    protected String flag;
 
     @SerializedName("comment")
     @Expose
-    public String comment;
+    protected String comment;
 
     @SerializedName("user_id")
     @Expose
-    public Long userId;
+    protected Long userId;
 
     /**
      * 同意申请